/*
 * Copyright (c) 2007 innoSysTec (R) GmbH, Germany. All rights reserved.
 * Original author: Edmund Wagner
 * Creation date: 24.05.2007
 *
 * Source: $HeadURL$
 * Last changed: $LastChangedDate$
 * 
 * 
 * the unrar licence applies to all junrar source and binary distributions 
 * you are not allowed to use this source to re-create the RAR compression algorithm
 *
 * Here some html entities which can be used for escaping javadoc tags:
 * "&":  "&#038;" or "&amp;"
 * "<":  "&#060;" or "&lt;"
 * ">":  "&#062;" or "&gt;"
 * "@":  "&#064;" 
 */
package com.github.junrar.rarfile;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.github.junrar.io.Raw;

/**
 * the header to recognize a file to be a rar archive
 * 
 * @author $LastChangedBy$
 * @version $LastChangedRevision$
 */
public class MarkHeader extends BaseBlock
 {

  private Log logger = LogFactory.getLog(MarkHeader.class.getName());
  private boolean oldFormat = false;

  public MarkHeader(BaseBlock bb)
   {
    super(bb);
   }

  public boolean isValid()
   {
    if (!(getHeadCRC() == 0x6152))
     {
      return false;
     }
    if (!(getHeaderType() == UnrarHeadertype.MarkHeader))
     {
      return false;
     }
    if (!(getFlags() == 0x1a21))
     {
      return false;
     }
    if (!(getHeaderSize() == BaseBlockSize))
     {
      return false;
     }
    return true;
   }

  public boolean isSignature()
   {
    boolean valid = false;
    byte[] d = new byte[BaseBlock.BaseBlockSize];
    Raw.writeShortLittleEndian(d, 0, headCRC);
    d[2] = headerType;
    Raw.writeShortLittleEndian(d, 3, flags);
    Raw.writeShortLittleEndian(d, 5, headerSize);

    if (d[0] == 0x52)
     {
      if (d[1] == 0x45 && d[2] == 0x7e && d[3] == 0x5e)
       {
        oldFormat = true;
        valid = true;
       }
      else if (d[1] == 0x61 && d[2] == 0x72 && d[3] == 0x21 && d[4] == 0x1a && d[5] == 0x07 && d[6] == 0x00)
       {
        oldFormat = false;
        valid = true;
       }
     }
    return valid;
   }

  public boolean isOldFormat()
   {
    return oldFormat;
   }

  public void print()
   {
    super.print();
    logger.info("valid: " + isValid());
   }
 }
